Preparation of an improved lubricant



cosity index which have erties; and relates particularly to lubricantscon- 'to, thicken thelubricant and also "polyisobutylene .well underconditions where lubrication of sur- I sulfur and chlorine ,as 2-methylpentadiene temperatures by the mide or'stannic T perature with elementselected from the sulfur group. -,;ji erred P386, P480 or P2865 1treatment very efiective Patented Aug..27, 1946 I PREPARATION ormmraovnnI LUBRICANT I David W. Young, Roselle, N. 1., Hlneline, Mount Vernon, N.

and Harris D. Y., assignors to- Standard Oil Development Companyga corporation of Delaware I No sawing, v

Appllcation luly s, 1944,

Serial No. 544,148 11 Claims. (crass-46.6)

1 This invention relates to thickened having an improved viscosityindex;

pcially relates esextremepressure proptaining phosphorous pentasulfidetreated, cyclicized polymer such as polymethyl pentadiene.

' A number of oil soluble substances have been fomid, which serve whendissolved in lubricants to improve its viscosity index; that is, toreduce the rate of I change of viscosity with change in temperature ofthe lubricant; among the best of which has been polyisobutylene.Polylsobutylene, however, lacks extreme pressure lubricating properties,and while the viscosit indexis excellent, it does not stand up facesunder extremely heavy pressure is required. On the other hand, varioussubstances have been offered which contain such inorganic radicals aswhich improve the extreme pressure properties of the'lubricant, but donot culty is encountered in adding both agents and obtainingsatisfactory results.

The present invention provides a single soluble addition agent which,tains both V. I. improving elementsand E. P. im-

proving elements and is found to yield an excellent viscosity index,and, simultaneously, excellent extreme pressure properties. v

For this purpose a polymerizable polyoleiin such 1,3- is polymerized atlow application of a Friedel Crafts catalyst dissolved in a lowfreezing, noncomplex formin lar weight polymer: which the application ofan appropriate cyclicizing agent such'as p-toluene sulionic acid oraluminum brochloride or The presubstance is phosphorous pentasulflde orP236 or P488 01' F286;. This mer) a considerable quantity of combinedphosphorous; which, together yield the high molecular weight or thecyclicized polylubricants to thickened lubricants of improved vis.

of a lubricating 011 containing improve the viscosity index; anddifiithe polyolefins having in a single substance, con per molecule,

, the like. The cyclic-. ized polymer is then treated at an elevatedtem-' a compound of phosphorous and an adds-into the cyclicized polymer(or into the oil blend containing the cyclic'lzed polyof combined sulfur(or selenium or tellurium) and a smaller quantity extreme pressureproperties whilepolymer which is preferred raw material is polymethyl pntadiene;

that is the polymer of 2, methyl 'pentadiene-1,3 v quite r'eadmer yieldsthe desired thickening and-the desired.

improvement in viscosity index. I

Thus the present invention provides a, new composition of mattercomprising a hydrocarbon solu-- tion of a cyclicized polymer suchaspolymethyl pentadiene containing combined sulfur, and smaller ornegligible quantities of combined phos phorous, dissolved in ahydrocarbon lubricant to yield a solution which remains liquid at lowtemperatures, and retains its body at relatively high temperatures.Other objects and details of the invention will be apparent from thefollowing dev scription.

The raw material for the present invention is a relatively highmolecular weight polyoleilnic capable of. cyclicization. The

which polymerizes at low temperature ily into high molecular weightpolymers, and when so polymerized cyclicizes quite readily. Afternativel almost any of the other high molecular weight polyolefinicpolymersare useful. Thus,

such polyolefins as 2,5-methyl pentadiene-1,3

or 2-methyl-5.-ethyl pentadiene-1,3 or the like are similarly useful.That is, substantially any of more than 5 carbon atoms in which there isan aliphatic sub- I stituent on the second carbon atom with a doublesolvent; to yield a high'molecuis, the cyclic-ized by I I Alternatively,other analogous compounds may be used,such for example as P453,

linkage between the first and second carbon atom, v

is useful. Those compounds which are c'onju gated, that is, contain twodouble linkages separated by a single linkage, are preferred, but thecondition of conjugation is not necessary.. The limiting molecularcarbon atoms per molecule polymerized and cyclicized, and are reactivewith phosphorous pentasulfide; fins including such ing the formula A Icmnmcncmcme-cmo'm are very desirable raw materials, since they poly- I-merize readily, cyclicize readily, are oil-soluble Y when polymerizedreadily with phosphorous pentasulflde after cy and cyclicized, andcombine cyclicization. Similarly, the triolefln known asalloocymene,having the formula I is qually advantageously useful. Thesesubsize of the compounds isstill unknown, but compounds as high as 12 or14 are useful. All of these dioleflns polymerize reasonably readily, 1-cyc'licize readily, are soluble in hydrocarbons when Similarly, thetriole substances as myrcene, havof good purity is used. In

noncomplex forming solvent.

Crafts halides, especially aluminum stances are representative ofpolyoleflns which polymerize at temperatures below C. into oil solublepolymers having molecular weightsabove 3000, 4000 or 5000, up to severalhundred thousand, with iodine numbers ranging from about 100 to 330 orabove, which are readily cyclicized to reduce the overall unsaturation,yet retain, in the cyclicized condition, sufiicient unsaturation to hereactive with phosphorous pentasulfide; and when so reacted, combinewith the phosphorous and sulfur in such a way that the solubility inhydrocarbons remains good, the inorganic atoms are solidly held so thatthe compound is stable, yet the inorganic molecules are so placed as toresult in an effective extreme pressure improvement.

Of these compounds, the polymer of methyl pentadiene is preferred.

In preparing this polymer, methyl pentadiene' after given, a methylpentadiene having a boiling point of 75 C. to 77 C. (at 760 mm. of Hg),9. density of 0.7113 and 1.4472 was used. This material has a puritybetter than 95 and further determinations indicate that its purity is infact approximately 98%. The methyl pentadiene is cooled to a temperatureabout between 0 C. and -l64= a temperature between -40 propane, and '103C.) as set by liquid C. as set by liquid ethylene.

The methyl pentadiene by itself may be, cooled, by the application of arefrigerating Jacket to the polymerization reactor. Alternatively themethylv diluted with such substances pentadiene may be as the lighterhydrocarbons or the alkyl, mono, or poiyhalides or carbon disulfide orthe like. Alternatively the methyl pentadienemay be cooled by aninternal reirigerant-diluent. For this purpose such substances as liquidpropane or liquid'ethane or The cold methylpentadiene is thenpolymerized by the application of a Friedel-0rafts catalyst whichpreferably is in solution in a low freezing The Friedel-Crafts catalystmay be substantially any of the substances disclosed on TheFriedel-Crafts Synthesis Journal of American Chemical $ociety atBaltimore in 1935 in volume XVII, No. 3, the article beginning on page327, the list being particularly well shown on page 375. TheseFriedel-Crafts active metal halides may be used as such in single salts,or

printed in the oral metals or several halides or even with alkoxysubstituents. These catalysts may be solid, liquid or gaseous (borontrifiuoride being gaseous; titanium tetrachloride being liquid; most ofthe remainder being solids). mouohalides are preferred such as methyl orethyl chloride. Other alkyl mono or peiyhalides having melting pointsbelow 0 C. are also useful; as is carbon disulfide. All of thesesubstances show an adequate solvent capacity for the Friedelchloridewhich is the preferred catalyst. Alternatively, and especially wherecatalyst complexes containing several halides, are used, the lighterhydrocarbons such as propane, butane, pentane, hexane, and the like maybe used; the principal requirements being a solubility of at least 0.5%for the examples hereinan index of refraction N C. (preferably to liquidethylene or even liquid methane may be used; or the material may bisbyN. 0. Galloway in his article Chemical Reviews, published for the Forsolvent, the alkyl the active methyl halides and a freezing point below0 C. (thereby being low freezing). The catalyst solution may be added tothe cold olefinic material in anyconvenient manner which 5 will bringthe catalyst solution quickly into intimate dispersion in the coldolefin. A convenient siredpolymer, and the conversion may be carried toa yield of from 40-50% of the amount of methylpentadiene present, to ayield as high as 90-95%. Such high yields are, however, less desirablesince the range of molecular weight is greater. When the reaction hasreached the desired stage, the catalyst supply is interrupted. The solidpolymer may be recovered in any desired manner; merely by boiling offresidual unpolymerized methylpentadiene; and refrigerate if present, orthe reaction mixture may be treated with warm water or warm alcohol orwarm naphtha, with or without small quantities of alcohol 'or the like.I v

The resulting polymer may have a molecular weight almost anywherebetween 2000, 3000 or -12,000 and 30,000-100,000, depending upon thelowness of the polymerization temperature, the

purity oi the methylpentadiene, the presence and purity ofdiluent-refrigerant, and the character of catalyst chosen. The preferredmolecular weight is within the and 35,000 to 45,000 since highermolecular somewhat more easily in service and lower molecular weightsrequire an rgim temperature and is ready for the dissolving S D.

Alternatively; the polymer may be dissolved in light naphtha and treatedwith stannic chloride at temperatures ranging from 20 C. to 00 C. fortime intervals ranging from 15 minutes to 80 hours. This treatment alsois effective for cyclicization, and likewise reduces the iodine numberto approximately 15 to 50.

Other methods which will be obvious to those skilled in the art maylikewise be used for this cyclicizs-tion step.

the phosphorous pentasulfide treatment.

The polymer is then dissolved in from 0.5% to 10% or 15% in the desiredhydrocarbon lubricant. For the production of a fluid lubricant, a highgrade, well refined oil having a viscosity at The reaction proceedsrapidly to yield the de- I range between about 5000 The polymer is thenready for desired values. is to be made,

150". C; to 225 C. for

' polymer be oil-soluble.

linkages, which I butylene, down to 0.-

210 F. of from 30 S. S. U. to '70 S. S. U. may be used, sufficientpolymer being dissolved in the oil to bring the viscosity and viscosityindex to the Alternatively, if a heavy grease a much heavier lubricantstock addition agents be incorporated; ofthe may be utilized and thevarious used to make heavy greases may together with from 1% to 15% or20% polymer.

To this solution there is then added a substantial quantity ofphosphorous pentasulfide, the

amount ranging from 1% to or of the amount of cyclicized polymer. Theoil solution is then heated to temperatures ranging from from 15 minutesto 150 minutes. The solution is then filtered to remove any uncombinedphosphorous pentasulflde, and

products, the material -being preferably filtered while hot because ofthe more rapid filtering rate. In the preparation. of greases it is, ofcourse, desirable that the auxiliary components be added after thefiltration step.

Th above outlined procedure applies particularly to methylpentadiene,and to its polymers,

any insoluble reaction but substantially the same procedure may beapplied to a wide range of polymerizable substances, polymers, and highmolecular weight substances in general, it being merely necessary thatthey be capable of cyclicizatlon; when cyclicized be soluble inhydrocarbons, and when cyclicized retain a suificiently high iodinenumher, and a sufficient amount of unsaturation to combine with thephosphorous pentasulfide.

Thus, for instance, an interpolymer of isobutylene with a polyolefinhaving more than 5 carbon atom in which a substantial quantity of thepolyolefin is interpolymerized, is similarly useful, especially withpolyolefins up to 12 or 14 carbon atoms per molecule and especially whenthe quantity of polyoleiin interpolymerized is subtion of sulfur withoutcross linkages retains the oil-solubility and it is of the essence ofthe present invention that, broadly, the polymer is cyclicized and'sulfurized without the introduction of cross linkage, in order toobtain a compound of high molecular weight which contains substantialquantities of combined sulfur (the effect of which is aided by thepresence of smaller quantities of phosphorous) and accordingly, theinvention is applicable to any polymer which can be 'cycliclzed andcombined with phosphorous pen-tasulfide without the formation ofsufiicient cross linkages to destroy the solubility in hydro- Example 1Approximately 100 parts of methyl pentadiene having a purity ofapproximately 95% were cooled to a temperature or approximately 88 C. bythe addition thereto of approximately 300 parts of liquid ethane. Themixture was then polymerized by the addition of approximately 50 partsof a solution of aluminum chloride in ethyl chloride having aconcentration of approximately 2%, the catalyst solution being sprayedon to the surface of the rapidly stirred oleflnic mixture. Thepolymerization proceeded quickly to yield a solid polymer having amolecular weight of approximately 40,000. The polymerization mixture wasthrown into hot water stantial in amount. That is, it is desirable thatthe polyoleiins having more than 5 carbon atoms, but not acharacteristic of butadiene, and the presence of butadiene per se to theextent of more than about 20% introduces so much cross linkage uponcyclicization as to render the cyclicized polymer useless. Thus,copolymers of isobutylene with butadiene or isc-prcne or piperylene,containing from 2% to 15% or 20% of butadiene are usable. Copolymers ofisobutylene with dimethyl butadiene, myrcene, dimethallyl and the like,up to 12 or 14 carbon atoms, are usable, especially when the proportionof interpolymerized diolefins exceeds 5% or 10%. Likewise, as will beevident from the above description, these polyolefins may be used withany proportion of isothe phosphorous pentato volatilize residualrefrigerant and to separate. unpolymerized methyl pentadiene. The yieldwas approximately 80%. lhe polymer was then placed on the double rollmill, washed with water until most of the residual traces of catalystwere removed. and then approximately 3 parts by weight (per hundred ofpolymer) of p-toluene. sulfonic acid were added and thoroughly milledinto the solid polymer. The milling was continued until a thoroughlyhomogeneous mixture was obtained. The solid mixture was then placed in ahot air ovenat 100 C. for 30 minutes.

The mixture was then cooled and approximately 50 parts by weight of thepolymer were dissolved in 1000 parts by weight of a high gradeparafilnic mineral lubricating oil which had a visis found to be acharacteristic of cosity at 210 1". of 52 S. S. U. and a V. I. of 98..When the solution was complete, yielding a clear fluid solution,approximately 50 parts by weight of powdered yellow phosphoricpentasulflde P285 was added, well stirred in and the mixture heated to atemperature of 180 C. for 30 minutes, the mixture being well stirredduring the heating step. At the end of the 30 minutes, the mixture wascooled to approximately 25 C. and filtered 55 through a paper filter toyield a clear filtrate.

Chemical analysis of the clear filtrate showed that it contained 0.58%of phosphorous and 2.03% of sulfur. v

Viscosity determinations and viscosity index determinations showed thefollowing inspection results:

, S.B.U.vis S.S.U.vls-

coslty at cosity at 210 V. I.

F. F. 488 74 l 131 These results show that the resulting oil has anexcellent viscosity and an excellent viscosity index.

Other portions of this oil product were then charged into the Almenmachine for the usual 30 second run. At the end of the 30 seconds, thesuccessive 2 lb. weights were added at 10 second interaeoaert vals untilthe full number or 15 weights had been added. The oil carried all 15weights. The pin an bushing were made of steel-and at the end of thetest the pin and bushing werein good condition.

Example 2 was then polymerized by the addition of approximately '75parts by volume of a solution or aluminum chloride in methyl chloride ina concentration or approximately 0.8%. The polymerization was conductedby spraying the catalyst solution onto the surface oil the rapidlystirred oleilnic material. The polymerization proceeded rapidly to yielda solid polymer having a molecular weight (by the Staudinger method) ofapproximately rescue. The polymerization mixture was then then thrownintowarm Water to volatilize residual traces of refrigerant and toseparate out any unpolymerized methyl pentadiene. The yield of polymerwas approximately 69%. The solid polymer was then placed on a doubleroll mill and washed with water until most of the residual traces ofcatalyst and monomer were removed.

When this stage was reached, approximately 10 parts by weight (per 100of polymer) of p-toluene sulfonic acid were added and thoroughly milledinto the solid polymer. The milling was continued until a thoroughlyhomogeneous mixture was obtained. The mixture was then-placed in a hotair oven at 100 C. minutes. lhe brown polymer mixture was then cooledand approximately 50 parts by weight of the polymer were dissolved in1000 parts by weight of a good lubricating oil which had a. viscosity at100 F. of 128 S. S. U., a viscosity at 210 F. of 42 S. S. U. and

v. I. of 109. When the solution was about complate, approximately 50parts by weight of powdered yellow phosphorous pentasulfide (Pass) wasadded and well stirred in. The mixture was then heated to a temperatureof 180 C. for 60 minutes, the mixture being well stirred during theheating period. At the end of the 60 minutes the mixture was cooled toapproximately 35 C. and filtered through a paper filter to removeresidual traces of, uncombined phosphorous pentasulilde'and to yield aclear filtrate. The filtrate was then blown with air, using about 5cubic feet per hour per kilo of solution for a period of 2 hours toremove traces of hydrogen sulfide and to deodorize the oil.

Chemical anaylsis or the clear, odorless filtrate showed that itcontained 0.8% of combined phosphorousand 2.88% of combined sulfur.Viscosity determinations and viscosity index determine:

tions showed the 'followinginspection results;

s. s. U. at s. s. U. at v.1.

d ried all 15 weights under this shock loading and after the test thepin and bushing. which were made of steel, were in good condition.

The oil was then tested under gradual loading conditions in the 'Almenmachine as outlined in Example 1. The cyclicized P255 treated polymer insolution in the oil carried all weights.

1 These results indicate that the oil prepared as a above described is ahigh grade lubricant having a very advantageous viscosity index and avery val.- uable extreme pressure property.

While there are above disclosed but a limited number of embodiments ofthe invention, it is out departing from the inventive concept hereindisclosed and it is, therefore, desired that only such limitations beimposed upon the appended claims as are stated therein or required bythe higher art. The invention claimed is:

1. An improved lubricant comprising a hydrocarbon lubricating agenthaving dissolved therein .5 to 20% of polymer of a polyolefin havingmore than 5 carbon atoms per molecule which is char-- acterized bycyclicization and the presence or phosphorous sulfide.

' 2. An improved lubricant comprising in combination a hyrh'ocarbonmaterial and a solute therein comprising .5% to 20% of a cyclicized.

comprising .5 to 20% of a cyclicized, phosphorous pentasulfide treated.polymer of myrcene. v

6. An improved lubricant comprising in com-- bination a hydrocarbon oiland a solute therein comprising .5 to 20% of a cyclicized, phosphorouspentachloride treated, polymer of allo-ocymene.

7. The method of preparing a lubricant comprising the steps incombination of polymerizing a polyolefin having from 6 to l'carbon atomsper moleculecyclicizing the polymer, treating the cyclicized polymerwith a compound of pliesphorous and an element from the sulfur group anddissolving .5 to 20% of the cyclicized phosphorous compound treatedpolymer in a lubricating material. I

-8. The method of preparing a lubricant com prising the steps incombination of polymerizing a. polyolefin having from 6 to 14 carbonatoms per molecule, cyclicizing the polymer, dissolving the cyclicizedpolymer in a hydrocarbon liquid, treating the cyclicizec polymer with acompound or phosphorous and an element from the sulfur group anddissolving .5 to 20% of the cyclicized phosphorous compound treatedpolymer in a. lu-

bricating material.

9. The process of preparing a lubricant come prising the steps incombination of polymerizing a methyl pentadiene, cyclicizing the methylpentadiene, dissolving .5 to 20% of the cycliclzeo possible to providestill-other embodiments witlobination a hydrocarbon oil and solutetherein I 9 v 7 methyl pentadiene in a. hydrocarbon lubricant,

and treating the dissolved polymer with phosphorous pentasulflde.

10. The process of preparing a lubricant comprising the steps incombination of polymerizing v a. methyl pentadiene, cyclicizing themethyl pentadiene by the application thereto of p-sulfonic acid,dissolving .5fto 20% of the cyclicized methyl pentadiene in ahydrocarbon lubricant, and treating the dissolved polymer withphosphorous pen- 10 V tasulflde. w

